Embodiments of the present disclosure generally relate to methods and devices for managing display of cardiac signals, and more particularly to manage display of cardiac signals based on data received from two or more asynchronous communications paths.
A next generation cardiac rhythm management (CRM) implantable medical device (IMD) has been proposed that utilizes Bluetooth Low Energy (BLE) telemetry to communicate with external instruments, such as a bedside monitor and/or programmer. Recently, it has been proposed that the monitor or programmer be configured to provide a scrolling display of real-time data. The programmer/monitor may receive two types of real-time data for monitoring heart rhythm, one is surface Electrocardiogram (ECG) data and the other is electrogram (EGM) data. The ECG data are recorded from the patient's body through a directly attached lead, while the EGM data are processed by the IMD and transmitted wirelessly to the programmer/monitor.
However, difficulties arise when the monitor/programmer attempts to display the ECG and EGM data simultaneously and in real-time. Even though both types of real-time data (ECG and EGM) are generated at the same time from the heart, the ECG and EGM data follow different paths as the data travel from the patient to the monitor or programmer. The different paths introduce different delays that cause the ECG and EGM data to arrive at the monitor or programmer out-of-sync. If left un-corrected, the out-of-sync data are presented to the user at the display of the monitor/programmer out of sync. Misleading information may be presented on the display if the ECG and EGM data are not presented in a coherent in-synch manner.
The dyssynchrony of the ECG and EGM data becomes even more prevalent when utilizing Bluetooth technology to transmit the EGM data from the IMD to the monitor/programmer. An inherent characteristic of a BLE protocol is the transmission of data in short bursts, not in a constant stream. While the BLE protocol seeks to utilize a maximum available BLE bandwidth, the BLE protocol is not optimized to provide EGM data in a manner that affords a smooth in sync scrolling display of real-time EGM traces. Also, the IMD introduces a certain amount of processing delay to process the EGM data and a communications delay to transmit the EGM data to the external monitor or programmer. The processing and communications delay introduce some constant and some in-deterministic delays which will make the display of real-time EGM data delayed and staggered with reference to corresponding ECG data.
Conventional approaches experience design challenges that do not compensate for the various delays and do not convert the short bursts of EGM data into a constant stream of EGM data at a desired rate. Conventional approaches do not display ECG and EGM data synchronized in a manner that enables a clinician to perform proper diagnosis.